NBT (New Breeding Techniques), or 'new GMOs', it is essential to strengthen the risk analysis. The scientific review published on Environmental Science Europe suggests deepening a debate that has been going on for at least 4 years continues under the track in the Old Continent.
The debate revolves around the hypothesis of progressively liberalizing the use of new plant varieties derived from genetic engineering. As already happens in the USA, where tens of thousands of them have been authorized in a few months.
Politics it is operated by Big 4, from one side of the Atlantic to the other. But the associations representing agroecology and organic productions try to resist. In the deafening silence of consumer associations (remote guided elsewhere, with strong powers) and del mainstream average, as usual. The ABC to follow.
Plant breeding and genetic engineering
The concept of plant breeding includes a wide range of techniques aimed at obtaining plants with certain genotypic and phenotypic characteristics. Mutagenesis - that is to say the mutation of a genome induced with physical (eg UV rays) or chemical agents (eg ethyl methanesulfonate) - dates back to the 30s.
The discovery of the structure of DNA and RNA and subsequent innovations in genetics and molecular biology allowed the birth, in the 70s, of genetic engineering. Genetic engineering techniques involve the introduction of different types of modifications in the genome of an organism, in order to obtain specific characteristics. By:
- transgenesis, that is, insertion into the genome of the host of genetic material coming from organisms of different species, or
- cisgenesis. The insertion of genes of the same species, the knock-out (removal or deactivation) or the silencing and / or overexpression of specific genes.
Figure 1. Comparison of four breeding techniques. Huang S, Weigel D, Beachy RN, Li J. A proposed regulatory framework for genome-edited crops. Nat Genet. 2016; 48 (2): 109-111. doi: 10.1038 / ng. 3484
nbt, New Breeding Techniques
The acronym NBT (New Breeding Techniques) expresses a set of new genetic engineering techniques developed in recent years. They differ from the techniques of editing genomic of the first generation (transgenesis) due to the prevalent use of genes belonging to the same target species. Without however excluding, in rare cases, the use of genetic material of different species than the one to be modified.
NBTs are currently classified into seven categories, further subdivided into two groups based on whether or not they use gene editing. The second group includes agroinfiltration, different epigenetic approaches, site-directed mutagenesis (or oligonucleotide-directed mutagenesis) and RNA interference (RNAi).
Gene-editing
Il gene editing is a type of genetic engineering that uses nucleases to perform targeted changes at specific points in an organism's genome. Insertion or removal of specific genes, or other types of modifications. With possible uses in agriculture and flower nursery (plant breeding), but also in the medical sector. With a view to developing innovative therapies for the treatment of various genetic diseases and cancers.
The main techniques di gene editing are the ZFN nucleases (Zinc Finger), the TALEN nucleases (Transcription Activator-like Effector Nucleases) and the CRISPR-Cas9 system.
CRISPR-Cas9
The CRISPR-Cas9 system is now the technique of editing most widespread genomic, thanks to its relative simplicity of use and the resulting versatility. CRISPR shortens the concept of Clustered Regularly Interspaced Short Palindromic Repeats, while Cas9 is the endonuclease used to perform the DNA cleavage.
This system it derives from a particular defense mechanism discovered in bacteria. Which, although not equipped with a real immune system, have developed protective mechanisms against infections of bacteriophage viruses and plasmids of other bacteria.
The peculiarity of CRISPR-Cas9 is the use of a guide RNA (gRNA) which is synthesized according to the needs. That is, based on the sequence of the genome to be targeted. This makes it possible to make cuts, within the genome, with a level of precision much higher than that of systems that exploit other types of nucleases.
Figure 2. Operation mechanism of CRISPR-Cas9. Razzaq A, Masood A (2018) CRISPR / Cas9 System: A Breakthrough in Genome Editing. Mol Biol 7: 210. doi: 10.4172 / 2168-9547.1000210
CRISPR-Cas9, technique and prerogatives
The synthesized gRNA 'tailor-made' binds to the Cas9 nuclease and is used as a probe, to identify the exact DNA sequence to cut. The Cas9 endonuclease in fact binds and flows on the DNA of the target organism, until it finds a PAM sequence (Protospacer Adjacent Motif) adjacent to the target sequence. At this point, if the gRNA binds complementarily to the target sequence, the Cas9-gRNA complex undergoes a conformational rearrangement that activates the nuclease domain of the enzyme and allows the DNA to be cut.
Double-strand breaks (DSB) thus introduced into the DNA are readily repaired by the cell itself. Through DNA damage repair mechanisms, which include the Non-Homologous End Joining (NHEJ) and homologous recombination systems (HDR). (1) In this way, the cell uses the DNA provided to it to 'repair the damage'. The CRISPR-Cas9 system can therefore be used to carry out site-specific sequence alterations, or to carry out deletions or insertions of genetic material in specific stretches of the target DNA. It is also possible to use multiple gRNAs to introduce changes at different sites of the target genome simultaneously or subsequently.
The modifications introduced by this technique are usually stable and therefore heritable, i.e. they are also transmitted to the offspring of the target organism. This technique also allows to overcome the natural systems of maintenance of the genome that protect its specific regions from the onset of random mutations.
The prerogative to obtain specific modifications on any part of the genome is impossible to achieve as quickly and effectively through conventional techniques of plant breeding. Instead, they are based on the induction of random mutations within the genome. For example, a variety of wheat with low gluten content was obtained which allowed an 85% decrease in immunoreactivity in celiac people.
GMOs old and new, the rules established in the European Union
The European Court of Justice (ECJ) was asked to decide on the discipline to apply to NBTs, as seen, in case C528 / 16 initiated by Confederation Paysanne and other organizations vis-à-vis the French government.
The Judges of Luxembourg, for once, disregarded the Opinion of the Advocate General. Affirming - with sentence 25.7.18, in case C-528/16 - that NBTs must comply with the rules already established for 'traditional' GMOs. Although formally excluded from the scope of Directive 2001/18 / EC on which it is based.
The deliberate issue in the environment of GMOs, old and new, it is therefore authorized by the European Commission, in agreement with the representatives of the Member States. Following a specific analysis of the possible risks for the environment and biodiversity by EFSA.
The use of GMOs and their derivatives in the production of food or feed is subject to further authorization. Which can be granted, again at European level, following a specific risk analysis by EFSA. Taking into account the potential impact of the consumption of substances deriving from or containing the GMO and / or its derivatives on human and animal health.
All GMOs placed in the environment and on the market in the European Union are in any case subject to precise obligations of traceability, labeling of food and feed, monitoring.
NBT, the hypotheses of reform of the EU rules
Breaking down the barriers release of NBTs into the environment, liberalize the trade of the same and of any commodity containing them. The Big 4, the global monopolists of pesticides and seeds, gave orders to the European Parliament already at the beginning of the legislature, as seen.
The European Commissioner to health and food safety, Stella Kyriakides, has thus announced the launch of a study on new genomic techniques, in spring 2021. With the ill-concealed objective of obtaining a motivation for the proposed reform of the GMO discipline on which, in Brussels, the usual suspects already work.
In spite of 'transparency' invoked on media and social networks, the Commission has been working for some time - with stakeholder which represent only the production chains, ca va sans dire - a document that European citizens and other interested social partners are excluded from knowing. And it is no coincidence that genetic engineering has also been included in the EU strategy Farm to Fork (f2f), as well as it has been seen.
Principle of precaution and risk analysis
Structural reform of the ecosystem that is advocated in the aforementioned technocratic design, however, cannot ignore the risk analysis and the precautionary principle on which European policies in terms of the environment, food and feed safety, public health and well-being are still based. animal (TFEU, Article 191.1).
Il network European of scientists for social and environmental responsibility (The European Network of Scientists for Social and Environmental Responsibility, ENSSER) has repeatedly expressed itself on the need to subject NBTs to accurate risk assessments. And so various molecular biologists and geneticists, like Dr. Michael Antoniou at King's College London.
Genetic manipulation it can in fact cause new combinations of gene functions that are not always precise as they are presented, nor predictable in subsequent interactions with complex systems. They can produce many unintended effects, not only at off-target sites but also at intended gene-editing sites.
Risk analysis on NBT, scientific review
La scientific review published on Environmental Science Europe by Andreas Bauer-Panskus et al. (2020) highlights how the protocols adopted by EFSA for risk analysis related to NBT need to be revised. As they are unable to adequately consider all the consequences that may derive from the introduction and persistence of these organisms in the environment. (2)
Researchers the Institute for Independent Impact Assessment of Biotechnology Munich therefore insist on the need to consider the next generation effects that may arise from the transmission of the new genetic material, also through interaction with environmental conditions.
'Consequentially, the biological characteristics of the original events cannot be considered sufficient to draw conclusions about the dangers that may emerge in subsequent generations. Potential hazards identified by the European Food Safety Authorization (EFSA) include aggravation of pest problems, displacement and even extinction of native plant species.
However, there are reasons for concern that could escape the environmental risk assessment (ERA). As EFSA takes into account only the characteristics of the original events, leaving aside the unintended or unforeseen next generation effects that emerge from spontaneous propagation and gene flow. '
Risk analysis and precautionary principle
The scientific review of the available publications and the analysis of the risk assessments carried out lead the researchers to conclude that the assessment of the risk of persistence and spontaneous propagation in the environment of NBTs is subject to a significant space-time complexity that causes many uncertainties. To address this problem, 'exclusion criteria' should therefore be established (cut-off criteria), in the risk assessment, considering the concrete limits of current knowledge.
The exclusion criteria proposed should be applied in a further and specific phase of the risk assessment, namely 'space-time controllability'. Using well-defined biological characteristics to delineate a boundary between known (and / or foreseeable) and unknown (and / or unpredictable) effects. According to the authors, this further phase of the risk assessment will promote the soundness of the process and will substantially benefit the overall reliability and completeness of the risk assessment. As well as on the decision-making process regarding deliberate releases into the environment of NBTs.
The European regulation of GMOs is based on the precautionary principle (Precautionary Principle). (3) This principle is characterized by the prevention of risks in the face of scientific uncertainty, with the aim of avoiding damage before a danger occurs.
Environmental risks not to be underestimated
The Munich researchers particularly focus on reproductive success (fitness) of plants obtained through gene editing, which in some cases is better than that of the corresponding natural varieties. An appreciable result - where intentional, in the perspective of commercial development - which at the same time deserves attention as regards the balance of ecosystems.
The increase of the fitness it can in fact overcome intentions and depend on the interaction of the new genetic material introduced with the rest of the genome or on a combination of the interaction of the new genetic material and the environmental conditions in which the plant is growing.
The genetic material introduced via gene editing it can also be transmitted to wild plants belonging to the same species, with different possible consequences on the hybrids. Such as an increase in the fitness or other effects on the genome that could manifest themselves in changes in plant physiology and metabolism. So finally on biodiversity, whose promise protection cannot ignore these assessments.
Dario Dongo, Riccardo Clerici, Silvia Comunian
Footnotes
(1) The NHEJ system is error prone and often causes the insertions or deletions of bases (indels) that alter the starting nucleotide sequence, and therefore if the double helix break occurs within the coding sequence of a gene or the regulatory sequence of a gene, this repair system can alter the functionality of that specific gene. The homologous repair system usually intervenes when the NHEJ fails to repair the double-strand break and uses homologous regions of the DNA to repair the damage. This system can also be exploited to introduce nucleotide replacements or to introduce insertions of specific sequences or to replace specific sequences within the target DNA simply by providing the cell with exogenous DNA with regions homologous to those adjacent to the cut.
(2) Bauer-Panskus, A., Miyazaki, J., Kawall, K. et al. Risk assessment of genetically engineered plants that can persist and propagate in the environment. Environ Sci Eur 32, 32 (2020). doi:10.1186/s12302-020-00301-0
(3) Dir. 2001/18 / EC, article 1. TFEU (Treaty for the Functioning of the European Union), article 191.2
(4) Garnett K, Parsons DJ (2016). Multi-case review of the application of the precautionary principle in European Union law and case law: application of the precautionary principle. Risk Anal 37:502–516. https://doi.org/10.1111/risa.12633
Dario Dongo, lawyer and journalist, PhD in international food law, founder of WIISE (FARE - GIFT - Food Times) and Égalité.
High school diploma, studies Biotechnology at the University of Milan Bicocca
